<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .red{
            background: red;
        }
        .blue{
            background: blue;
        }
    </style>
</head>
<body>
<!-- 1.1～1.5、【增】 -->
  <div>
    <div id="test">
        <span>test1</span>
        <p class="red">段落标签31</p> test2
    </div>
      <div id="test2">
          <p class="red">段落标签32</p> test2
      </div>
  </div>
<!-- 2.1～2.2、【删】 -->
  <div id="empty">
      <div id="e1"></div>
      <div id="e2"></div>
      <div id="e3"></div>
  </div>
  <div id="siblings">
      <div id="s1"></div>
      <div id="s2"></div>
      <div id="s3"></div>
  </div>
  <div id="travel">
    <div id="t1">1</div>
    <div id="t2">2</div>
    <div id="t3">3</div>
  </div>
  <script src="dom.js"></script>
  <script src="testCase.js"></script>
</body>
</html>